2021 RAM CHASSIS CAB brake light

114GETTING TO KNOW YOUR INSTRUMENT PANEL
Cold Ambient Derate Mode Indicator
Light — If Equipped
This indicator light will illuminate
when a derate (engine power
reduction) is activated for protection
of the turbocharger in cold ambient
temperatures.
Diesel Exhaust Brake Indicator Light — If
Equipped
This indicator light will illuminate
when the Diesel Exhaust Brake has
been activated, and is in full strength
mode Ú page 138.
4WD Lock Indicator Light
This light alerts the driver that the
vehicle is in the 4WD LOCK mode.
The front and rear driveshafts are
mechanically locked together, forcing
the front and rear wheels to rotate at the same
speed Ú page 153.
4WD Low Indicator Light — If Equipped
This light alerts the driver that the
vehicle is in the 4WD Low mode.
The front and rear driveshafts are
mechanically locked together forcing the front and rear wheels to rotate at the same
speed. Low range provides a greater gear
reduction ratio to provide increased torque at
the wheels Ú
page 153.
4WD High Indicator Light — If Equipped
This light alerts the driver that the
vehicle is in the 4WD High mode.
The front and rear driveshafts are
mechanically locked together forcing
the front and rear wheels to rotate at the same
speed.
NEUTRAL Indicator Light — If Equipped
This light alerts the driver that the
4WD power transfer case is in the
NEUTRAL mode and the front and rear
driveshafts are disengaged from the
powertrain.
Low Diesel Exhaust Fluid (DEF) Indicator
Light — If Equipped

The Low DEF Indicator will illuminate if
the vehicle is low on DEF
Ú
page 379.

Wait To Start Light — If Equipped
This indicator light will illuminate for
approximately two seconds when the
ignition is turned to the RUN position.
Its duration may be longer based on
colder operating conditions. Vehicle will not
initiate start until telltale is no longer displayed
Ú page 122.
NOTE:

The “Wait To Start” telltale may not illuminate if the
intake manifold temperature is warm enough.

Water In Fuel Indicator Light — If Equipped
The “Water In Fuel Indicator Light”
will illuminate when there is water
detected in the fuel filter. If this light
remains on, DO NOT start the vehicle
before you drain the water from the fuel filter to
prevent engine damage Ú page 375.

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GETTING TO KNOW YOUR INSTRUMENT PANEL115
GREEN INDICATOR LIGHTS
Adaptive Cruise Control (ACC) Set With
Target Light — If Equipped
This will display when the ACC is set
and a the vehicle in front is detected
Úpage 166.
Adaptive Cruise Control (ACC) Set With
No Target Detected Indicator Light — If
Equipped
This light will turn on when the
Adaptive Cruise Control is SET and
there is no vehicle in front detected
Úpage 166.
Automatic Diesel Exhaust Brake Indicator
Light — If Equipped
This indicator light will illuminate
when the Diesel Exhaust Brake has
been activated, and has switched to
Automatic mode Ú page 164.
ECO Mode Indicator Light — If Equipped
This light will turn on when ECO Mode
is active.
Park/Headlight On Indicator Light
This indicator light will illuminate
when the park lights or headlights are
turned on.
Front Fog Indicator Light — If Equipped
This indicator light will illuminate
when the front fog lights are on.
Turn Signal Indicator Lights
When the left or right turn signal is
activated, the turn signal indicator
will flash independently and the
corresponding exterior turn signal
lamps will flash. Turn signals can be activated
when the multifunction lever is moved down
(left) or up (right).
NOTE:
A continuous chime will sound if the vehicle is
driven more than 1 mile (1.6 km) with either
turn signal on.
Check for an inoperative outside light bulb if
either indicator flashes at a rapid rate.
If equipped with fog lamps, the fog lamp on
the side of the activated turn signal will also
illuminate to provide additional light when
turning.
Cruise Control Set Indicator Light — If
Equipped
This indicator light will illuminate
when the cruise control is set to the
desired speed Ú page 164.
WHITE INDICATOR LIGHTS
Adaptive Cruise Control (ACC) Ready
Light — If Equipped
This light will illuminate when the
vehicle equipped with ACC has been
turned on but not set Ú page 166.
Cruise Control Ready Indicator
This indicator light will illuminate
when the cruise control is ready, but
not set Úpage 164.
Set Speed Display
The Set Speed Display indicator light
indicates the set speed for the Speed
Control and ACC settings.
3

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124STARTING AND OPERATING
ENGINE START/STOP Button Functions — With
Driver’s Foot OFF The Brake Pedal (In PARK Or
NEUTRAL Position)

The ENGINE START/STOP button operates similar
to an ignition switch. It has three positions, OFF,
ACC, RUN. To change the ignition switch positions
without starting the vehicle and use the
accessories follow these steps:

1. Start with the ignition in the OFF position.

2. Push the ENGINE START/STOP button once
to change the ignition to the ACC position.
3. Push the ENGINE START/STOP button a second time to change the ignition to the
RUN position.
4. Push the ENGINE START/STOP button a third time to return the ignition to the OFF
position.Keyless Enter-N-Go Starting Procedure —
Engine Manifold Air Temperature
0°F To 66°F (–18°C to 19°C)
NOTE:
The temperature displayed in the instrument
cluster does not necessarily reflect the engine
manifold air temperature Ú page 90. When
engine temperatures fall below 66°F (19°C)
the “Wait To Start” telltale will remain on indi -
cating the intake air heater system is active.
Follow the steps in the “Normal Starting”
procedure except:

1. Pushing the engine start button with the driver’s foot on the brake will move the
ignition from OFF or ACC to RUN, and
will illuminate the "Wait to Start" telltale.
The engine will not immediately crank, this
is normal operation.

2. The “Wait to Start" telltale will remain on for a period of time that varies depending on
the engine temperature.
3. While the "Wait to Start" telltale is on, the instrument cluster will additionally display a
gauge or bar whose initial length represents the full "Wait to Start" time period. Its length
will decrease until it disappears when the
"Wait to Start" time has elapsed.
4. After the engine “Wait to Start” telltale goes off, the engine will automatically crank.
5. After engine start-up, check to see that there is oil pressure.
6. Release the parking brake and drive.CAUTION!
If the “Water in Fuel Indicator Light” remains
on, DO NOT START the engine before you
drain the water from the fuel filters to avoid
engine damage Ú page 375.
CAUTION!

Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.

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STARTING AND OPERATING125
NOTE:
Engine idle speed will automatically increase
to 1,000 RPM and engage the Variable
Geometry Turbocharger at low coolant
temperatures to improve engine warm-up.
The engine will not automatically crank after
the engine "Wait to Start" telltale goes off if a
door or the hood is ajar.

If the engine stalls, or if the ignition switch is
left ON for more than two minutes after the
“Wait to Start” telltale goes out, reset the
intake air heater by turning the ignition switch
to the OFF position for at least 5 seconds and
then back ON. Repeat steps 1 through 6 of
“Keyless Enter-N-Go Starting Procedure –
Engine Manifold Air Temperature 0°F To 66°F
(–18°C to 19°C).”

EXTREME COLD WEATHER
The Cummins Turbo Diesel engine is equipped
with several features designed to assist cold
weather starting and operation:

The engine block heater is a resistance heater
installed in the water jacket of the engine just
above and behind the oil filter. It requires a 110–115 Volt AC electrical outlet
with a grounded, three-wire extension cord.

NOTE:
The engine block heater cord is a factory
installed option. If your vehicle is not equipped,
heater cords are available from an authorized
Mopar dealer.
A 12 Volt heater built into the fuel filter hous -
ings aid in preventing fuel gelling. It is
controlled by a built-in thermostat.
An intake air heater system both improves
engine starting and reduces the amount of
white smoke generated by a warming engine.
NORMAL STARTING PROCEDURE —
E
NGINE MANIFOLD AIR TEMPERATURE
A
BOVE 66°F (19°C)
Observe the instrument panel cluster lights
when starting the engine.

1. Always apply the parking brake.

2. Shift into PARK for an automatic
transmission. 3. Place the ignition switch in the ON position
and watch the instrument panel cluster
lights.
4. Place the ignition switch in the START position and crank the engine. Do not press
the accelerator during starting.
5. Check that the oil pressure warning light has turned off.
6. Release the parking brake.
CAUTION!
If the “Water in Fuel Indicator Light” remains
on, DO NOT START the engine before you
drain the water from the fuel filters to avoid
engine damage Ú page 375.
CAUTION!

Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.

4

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126STARTING AND OPERATING
STARTING PROCEDURE — ENGINE
M
ANIFOLD AIR TEMPERATURE 0°F TO
66°F (–18°C
TO 19°C)
NOTE:
The temperature displayed in the instrument
cluster does not necessarily reflect the engine
manifold air temperature Ú page 90. When
engine temperatures fall below 66°F (19°C)
the “Wait To Start” telltale will remain on indi -
cating the intake air heater system is active.
Follow the steps in the “Normal Starting”
procedure except:

1. The “Wait to Start” telltale will remain on for a period of time that varies depending
on the engine temperature.

2. While the “Wait to Start” telltale is on, the instrument cluster will additionally display a
gauge or bar whose initial length represents
the full “Wait to Start” time period. Its length
will decrease until it disappears when the
“Wait to Start” time has elapsed. 3. After the “Wait to Start” telltale goes off,
place the ignition switch in the START
position. Do not press the accelerator
during starting.
4. After engine start-up, check that the oil pressure warning light has turned off.
5. Release the parking brake and drive. NOTE:
Engine idle speed will automatically increase
to 1,000 RPM and engage the Variable
Geometry Turbocharger at low coolant
temperatures to improve engine warm-up.

Automatic equipped vehicles with optional
Keyless Enter-N-Go – If the ENGINE START/
STOP button is pushed once while in PARK
with the ignition off and driver’s foot on the
brake pedal, the vehicle will automatically
crank and start after the “Wait to Start” time
has elapsed. If it is desired to abort the start
process before it completes, the driver’s foot
should be fully removed from the brake pedal
prior to pushing the start button again in order
for the ignition to move directly to off.
If the engine stalls, or if the ignition switch is
left ON for more than two minutes after the
“Wait To Start” telltale goes out, reset the
intake air heater by turning the ignition switch
to the OFF position for at least five seconds
and then back ON. Repeat steps 1 through 5 of
“Starting Procedure – Engine Manifold Air
Temperature 0°F To 66°F (–18°C to 19°C).”

CAUTION!
If the “Water in Fuel Indicator Light” remains
on, DO NOT START the engine before you
drain the water from the fuel filters to avoid
engine damage Ú
page 375.
CAUTION!

Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.

21_DPF_OM_EN_USC_t.book Page 126

128STARTING AND OPERATING
STARTING FLUIDS
The engine is equipped with an automatic
electric air preheating system. If the
instructions in this manual are followed,
the engine should start in all conditions.
NORMAL OPERATION — DIESEL ENGINE
Observe the following when the engine is
operating.
All message center lights are off.
Malfunction Indicator Light (MIL) is off.
Engine oil pressure is above 10 psi (69 kPa)
at idle.
Voltmeter operation:

The voltmeter may show a gauge fluctuation
at various engine temperatures. This cycling
operation is caused by the post-heat cycle of the
intake manifold heater system. The number of
cycles and the length of the cycling operation
is controlled by the engine control module.
Post-heat operation can run for several minutes,
and then the electrical system and voltmeter
needle will stabilize.

The cycling action will cause temporary
dimming of the headlamps, interior lamps, and
also a noticeable reduction in blower motor
speed.
WARNING!
Starting fluids or flammable liquids must
never be used in the Cummins diesel engine
(see Warning label). Never pour diesel fuel,
flammable liquid, starting fluids (ether) into
the air cleaner canister, air intake piping, or
turbocharger inlet in an attempt to start the
vehicle. This could result in a flash fire and
explosion causing serious personal injury and
engine damage.
WARNING!
Do not leave children or animals inside
parked vehicles in hot weather. Interior
heat build-up may cause serious injury or
death.
When leaving the vehicle, always remove
the key fob and lock your vehicle.

Never leave children alone in a vehicle, or
with access to an unlocked vehicle. Allowing
children to be in a vehicle unattended is
dangerous for a number of reasons. A child
or others could be seriously or fatally injured.
Children should be warned not to touch the
parking brake, brake pedal or the gear
selector. Do not leave the key fob in or near
the vehicle (or in a location accessible to chil -
dren), and do not leave the ignition of a
vehicle equipped with Keyless Enter-N-Go in
the ACC or ON/RUN mode. A child could
operate power windows, other controls, or
move the vehicle.

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STARTING AND OPERATING131
Your vehicle is equipped with an engine
warm-up protection feature that may limit
engine performance after cold starting at low
ambient temperatures. The length of time
engine speed is limited is dependent upon
engine coolant temperature. Engine speed may
be briefly limited to 1,000 RPM after starting
with coolant temperature below freezing
conditions, and may be limited to 1,000 RPM
for up to approximately two minutes under more
severe cold conditions.
NOTE:
If ambient temperatures are low and the
coolant temperature is below 180°F (82°C),
the engine idle speed will slowly increase to
1,000 RPM after two minutes of idle, if the
following conditions are met:
Foot is off brake pedal and throttle pedal.
Automatic transmission is in PARK.
Vehicle speed is 0 mph (0 km/h).
Applying the throttle will cancel fast idle.
Operating the exhaust brake at idle will
greatly improve warm-up rate and will help
keep the engine close to operating tempera -
ture during extended idle.
ENGINE IDLING
Avoid prolonged idling, long periods of idling
may be harmful to your engine because
combustion chamber temperatures can drop
so low that the fuel may not burn completely.
Incomplete combustion allows carbon and
varnish to form on piston rings, engine valves,
and injector nozzles. Also, the unburned fuel
can enter the crankcase, diluting the oil and
causing rapid wear to the engine.

If the engine is allowed to idle or the truck is
driven on low engine speed drive cycles for more
than two hours, the system will automatically
enter an emissions operating mode that will
increase the engine idle speed to 900 RPM
(1,050 RPM for Chassis Cab). While in this mode,
which is designed to help maintain the Diesel
Particulate Filter, the engine idle speed will return
to normal when the brake pedal is applied.
A small change in engine tone or a slight change
in engine performance while accelerating may
also be noticeable at speeds below 20 mph
(32 km/h). This operating mode may last for up
to an hour of idle time, or around 20 minutes of
driving time. Your truck may have been ordered with an
optional voltage monitoring idle up feature. If a
load is placed on the electrical system while the
truck is in PARK, this feature will attempt to
maintain normal system voltage by automatically
increasing engine idle speed. You may notice
several consecutive increases in idle speed, up to
a maximum of 1,450 RPM, as the system will
attempt to utilize the smallest increase in idle
speed necessary to maintain normal system
voltage. The idle speed will return to normal when
either the electrical load is removed, or when the
brake pedal is applied.

NOTE:
For instrument cluster display messages
related to the vehicle's exhaust system
Ú
page 90.
4

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132STARTING AND OPERATING
Idle-Up Feature

The driver-controlled high idle speed feature will
help increase cylinder temperatures and provide
additional cab heat, however, excessive idling may
still cause the exhaust after-treatment system to not
properly regenerate. Extended periods of idle time
should be avoided.

The Idle-Up feature uses the Cruise Control
buttons to increase engine idle speed and
quickly warm the vehicle's interior.

1. With the transmission in PARK, the parking
brake applied, and the engine running,
turn on the Cruise Control, then push the
SET (-) button.

2. The engine RPM will go up to 1,100 RPM. To increase the RPM, push and hold the
RES (+) button and the idle speed will
increase to approximately 1,500 RPM.
To decrease the RPM, push and hold the
SET (-) button and the idle speed will
decrease to approximately 1,100 RPM. 3. To cancel the Idle–Up feature, either push
the CANCEL button, push the ON/OFF
button, or press the brake pedal.
NOISE
Diesel engines can create noises that may
seem as a concern. The nature of a diesel
engine is compression ignition where
compressed air and fuel are mixed and ignited.
Weather, barometric pressure, altitude and
temperature will affect how fuel is ignited in the
engine. Engines will sound different from day to
day or previous model years. Clicking, ticking, or
light knocking is normal and will change from
day to day, as the engine breaks in, and can
vary with changes in ambient temperature; this
is normal. Diesel equipped vehicles also have
an exhaust after treatment system to reduce
emissions utilizing a Diesel Particulate Filter
(DPF) and a Selective Reduction Catalyst (SCR). The SCR reduces Nox using the Diesel Exhaust
Fluid (DEF) system. DEF is injected directly into
the SCR through an dosing module. This
process will create a clicking sound and at
times, will make noise even with the vehicle
shut off. This is normal as the DEF dosing
module is purging DEF. Fuel pump noise may
increase during low speed/light load conditions
when ambient temperature is above 100°F
(38°C), and when fuel tank level is below 10%.
This is a normal condition of the fuel system and
controls strategy. If at any time the check
engine light is on, please visit an authorized
dealer.

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